1. Technical Field
The present disclosure relates to a method for preparing cathode active materials of batteries and, particularly, to a method for preparing a cathode active material of a lithium battery.
2. Description of Related Art
In recent years, lithium batteries have received a great deal of attention. Lithium batteries are used in various portable devices, such as notebook PCs, mobile phones, and digital cameras because of their small weight, high discharge voltage, long cycle life, and high energy density compared with conventional lead storage batteries, nickel-cadmium batteries, nickel-hydrogen batteries, and nickel-zinc batteries.
A lithium battery is made up of a cathode and an anode, each having an active material capable of reversibly doping/un-doping at the least, lithium ions and a non-aqueous electrolyte. The charging reaction of the lithium battery process includes lithium ions being deintercalated into an electrolyte solution at the cathode active material and are intercalated into the anode active material. In discharging, an opposite reaction to that of the charging reaction proceeds, such that lithium ions are intercalated at the cathode.
At present, the most widely used cathode active materials are spinel type lithium manganese oxide (e.g. LiMn2O4), olivine type lithium iron phosphate (e.g. LiFePO4), and layered type lithium cobalt oxide (e.g. LiCoO2). LiFePO4 has a volumetric density as high as 3.6 g/m3 and generates a high potential of 3.4 V, with a theoretical capacity as high as 170 mAh/g. Further, LiFePO4 includes iron, an inexpensive material plentiful in supply, in its composition, and therefore is less costly. There are many methods which have been proposed for preparing LiFePO4 such as a solid state synthesis method, a hydrothermal synthesis method, a chemical co-precipitation synthesis method, and a microwave synthesis method. However, most of the above described methods have mass production problems.
What is needed, therefore, is to provide a simple and low cost method for preparing the cathode active material which is suitable for mass production.